High-vacuum coating apparatus

ABSTRACT

A high-vacuum coating apparatus for coating films has beneath its coating cylinder (7) a pivoting unit (8) which can turn on a pivot shaft (25). It has an adjustable mask (29) and thereunder a shutter (28) which can run from a position covering an evaporator to a position releasing it. Due to its ability to turn, the pivoting unit (8) together with its parts can easily be cleaned.

The invention relates to a high-vacuum coating apparatus for coating afilm which is carried in an evacuable vacuum tank over a coatingcylinder disposed when in the working position above an evaporator andable to be rolled out the vacuum tank by a floor running unit, and inwhich, in order to define the coating area, an adjustable mask definingthe coating area is disposed beneath the coating cylinder, plus amovable shutter for the complete covering of the evaporator.

Coating apparatus of the above kind are used for coating films with ametal overlay and are generally known. They have a floor running unitrunning on tracks, which can be brought with a tank plate sealinglyagainst an open end face of the vacuum tank. A winder, an unwinder and acoating cylinder extend out of the tank plate. When this coatingcylinder enters into the vacuum tank it comes over the evaporatorstationarily mounted in the vacuum tank.

The shutter which covers the evaporator before and after the coatingprocess is, in the known apparatus, disposed on the evaporator in thevacuum tank and therefore is not easily accessible for cleaning. Themask is provided on the floor running unit so as to be able to swingunder the coating cylinder, but it is nevertheless poorly accessible,since even in the state in which it is swung away from the coatingcylinder it is in an undesirably low, poorly accessible position.

The invention is addressed to the problem of improving a high-vacuumcoating apparatus of the kind described above such that, when it isopen, its mask and shutter will be very easily accessible for cleaning.

This problem is solved according to the invention in that the mask andthe shutter are provided on a pivoting unit which is hinged parallel tothe coating cylinder, in front of the latter, on the floor-running unit.

By this combining of the shutter and mask in a single turning unit, andby the fact that its pivot shaft is in front of the coating cylinder,the shutter and the mask can be turned to a position in which thesurfaces to be cleaned are easily accessible.

The pivoting unit is of especially compact construction and makesoptimum use of the space available in the high-vacuum coating apparatusif, according to a further development of the invention, the shutter isdisposed to travel on straight guides on the pivoting unit.

After being turned away from the coating cylinder, the pivoting unit isat a sufficient distance away from it to be easily accessible as well,and to permit cleaning of the coating cylinder if, according to anotherembodiment of the invention, the pivoting unit is L-shaped as seen fromthe side, and the pivot shaft in front of the coating cylinder is in theshorter limb of the L.

The vacuum tanks of known high-vacuum coating apparatus were heretoforealways round in cross section, and the evaporator was always on aboutthe vertical center line of the vacuum tank. The winders and unwinderswere at a level above the evaporator to the right and left of it, sothat the coating cylinder could be disposed between them directly abovethe evaporator. Thus the coating cylinder and accordingly also the maskcarried by the floor-running unit were at a relatively great distancefrom the front of the apparatus, which made access difficult. Thecoating cylinder with the mask and shutter are optimally accessible if,according to an especially advantageous further improvement of theinvention, the vacuum tank has a rectangular cross section and theevaporator and therefore also the coating cylinder is disposedoff-center near the front wall of the vacuum tank, and if the pivotshaft runs between the coating cylinder and the front wall of the vacuumtank.

Usually in high-vacuum coating apparatus an airlock is formed above thecoating cylinder by means of airlock jaws, and permits the achievementof a very high vacuum in the coating chamber. These airlock jaws can beintegrated into the pivoting unit if, according to another furtherimprovement of the invention, the pivot unit has two longitudinal rails30 running parallel to one another at a distance apart, which, when thepivoting unit is swung under the coating cylinder, reaches with anarcuately curved surface directly facing the coating cylinder to form asealing gap.

The invention is susceptible of numerous forms of embodiment. For abetter comprehension of its basic principle, one of them is representedin the drawing and is described below.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the drawings:

FIG. 1 is a side view of a high-vacuum coating apparatus according tothe invention,

FIG. 2 is a diagrammatic cross section through a vacuum tank of thecoating apparatus,

FIG. 3 is a representation on a larger scale than in FIG. 2 of thecoating cylinder with the adjacent components, and

FIG. 4 is a cross section through a portion of the vacuum tank with apivoting unit swung out.

FIG. 1 shows a vacuum tank 1 of rectangular cross section in which thecoating process takes place. On the right above the vacuum tank 1 is afloor-running unit 2 which can run on rails 3. The floor-running unit 2has a tank plate 4 which, by running the floor-running unit 2 leftwardcan be set sealingly against the right end of the vacuum tank 1. Awinder 5 and an unwinder 6 extend from the tank plate 4 toward thevacuum tank 1. Furthermore, at a level about half-way between the winder5 and unwinder 6 is shown a coating cylinder 7 and below it a pivotingunit 8. Winding motors 9 and 10 on the side of the tank plate 4 facingaway from the vacuum tank 1 serve for driving the winder 5 and unwinder6. A bearing plate 11 on the side of the floor-running unit 2 facing thevacuum tank 1 carries the ends of the winder 5 and unwinder 6 remotefrom the tank plate 4. To prevent the floor-running unit 2 from tippingdue to the masses disposed in front of its tank plate 4 in FIG. 1, thefloor-running unit 2 is supported at its frontmost and topmost pointfacing the vacuum tank 1 by wheels 12 on a beam 13 extending from thetop of the vacuum tank 1.

Two diffusion pumps 14 and 15 are disposed underneath the vacuum tankfor the evacuation of the vacuum tank 1. Also, a set of mechanical pumps16, 16a, 17 and 18 is situated in back of the vacuum tank. At the startof a coating process a roll of the film to be coated is pushed onto thewinder 5 and the film 20 is then guided over pulley rolls not shown andthe coating cylinder 7 to the winder 5. Then the floor-running unit 2 isrolled into the vacuum tank 1 until its tank plate 4 closes the vacuumtank 1. Then the vacuum tank is evacuated by the mechanical pumps 16-18and part of it by the diffusion pumps 14 and 15.

FIG. 2 shows diagrammatically in the vacuum tank 1, the unwinder 6 andabove it the winder 5. Also it can be seen that the coating cylinder 7is situated in front of the winder 5 and the unwinder 6 at a level abouthalfway between the two. The film 20 that is to be coated runs from asupply roll 21 on the unwinder 6, over the coating cylinder 7, to atake-up roll 22 on the winder 5.

On the front wall 23 of the vacuum tank 1 there is disposed adjacent itsfront wall 23 an evaporator 24. From the latter the coating materialevaporates against a coating area of the film 20 on the coating cylinder7, passing through the pivoting unit 8. The latter is approximatelyL-shaped and is hinged about a pivot shaft 25 running directly behindthe front wall 23 of the vacuum tank 1 in front of the coating cylinder7 through the shorter leg 26 of the L. FIG. 2 furthermore shows adividing wall 34 which divides the vacuum tank 1 into a coating chamber35 and a winding chamber 36.

FIG. 3 shows that the pivoting unit 8 has a shutter 28 which can run ona rectilinear guide 27 and which in the position represented covers thetop of the evaporator 24. Above the shutter 28 can be seen two sideparts of a mask 29 which defines the cross section of the passage of theevaporated metal toward the coating cylinder 7.

Two longitudinal legs 30 and 31 of the pivoting unit 8 are representedin broken lines in FIG. 3, each having a surface 32, 33, of circularcurvature directly facing the coating cylinder 7 with which it forms anarrow air gap. These legs 30 and 31 form an airlock through which theflow of air from the winding chamber 36 shown in FIG. 2 to the coatingchamber 35 is limited.

The rearward position of the shutter 28, in which the evaporator 24 isfree and the coating process is running, is indicated in broken lines inFIG. 3.

FIG. 4 shows the pivoting unit 8 in its position swung away from thecoating cylinder 7, which of course is possible only when thefloor-running unit 2 with the coating cylinder is rolled out of thevacuum tank 1. It can be seen that, in this position the shutter 28 andthe mask 29 are easily accessible.

While there has been described what is at present considered to be thepreferred embodiment of this invention, it will be obvious to thoseskilled in the art that various changes and modifications may be madetherein without departing from the invention, and it is, therefore,aimed to cover all such changes and modifications as fall within thetrue spirit and scope of the invention.

What is claimed is:
 1. High-vacuum coating apparatus for coating a filmcomprising: an evacuable vacuum tank, an evaporator, a coating cylinder,the evacuable vacuum tank being over the coating cylinder which isdisposed in working position above the evaporator and is movable out ofthe vacuum tank, a floor-running unit for moving the coating cylinderand including an adjustable mask, defining the coating area, which isdisposed underneath the coating cylinder and a displaceable shutter forthe complete covering of the evaporator, a pivot shaft disposed parallelto and in front of the coating cylinder of the floor-running unit, apivoting unit which is hinged about the pivot shaft, the mask and theshutter being on the pivoting unit.
 2. High-vacuum coating apparatusaccording to claim 1, in which the pivoting unit includes rectilinearguides and in which the shutter is disposed for running on therectilinear guides.
 3. High-vacuum coating apparatus according to claim1, in which the pivoting unit is L-shaped having a shorter limb as seenfrom the side and in which the pivot shaft runs in front of the coatingcylinder in the shorter limb of the L.
 4. High-vacuum coating apparatusaccording to claim 1, in which the vacuum tank has a rectangular crosssection and a front wall, and the evaporator and the coating cylinderare disposed off-center near the front wall of the vacuum tank, and inwhich the pivot shaft runs between the coating cylinder and the frontwall of the vacuum tank.
 5. High-vacuum coating apparatus according toclaim 1, in which the pivoting unit has two longitudinal rails runningparallel to one another at a distance apart, and in which, when thepivoting unit is swung under the coating cylinder, each rail has anarcuately curved surface which reaches to immediately in front of thecoating cylinder with the formation of a narrow gap.